Intrinsic lifetimes of acoustic phonons in superlattices

The intrinsic lifetime of acoustic phonons in a two-component superlattice is calculated in the low-temperature regime. The layers forming the superlattice have been chosen to be isotropic, and the acoustic phonon frequencies and eigenvectors have been calculated with the help of transfer matrices. The anharmonic coupling coefficients have been determined using the second-order and third-order elastic moduli of the two constituents. The thermoelastic contribution to the damping constant at room temperature is calculated and compared to corresponding values in homogeneous media. (C) 1999 Elsevier Science B.V. All rights reserved.